Terminal device, base station, and communications method of terminal device and base station

ABSTRACT

Information about amounts of to-be-transmitted data of a communication group may be reported to a base station, so that the base station can schedule data for the communication group. The information about the amount of the to-be-transmitted data includes identification information of the communications group, and a buffer status report of a logical channel group corresponding to the communications group.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/346,080, filed on Nov. 8, 2016, which is a continuation ofInternational Application No. PCT/CN2014/077176, filed on May 9, 2014,All of the afore-mentioned patent applications are hereby incorporatedby reference in their entireties.

TECHNICAL FIELD

Embodiments of the present invention relate to the communications field,and in particular, to terminal device, a base station, and acommunications method of the terminal device and the base station.

BACKGROUND

In an existing cellular communications technology, a user terminalcommunicates with a base station by using an air interface, and forwardsuser data to a destination node in a network through the base station.

A device-to-device (D2D) communications technology is a technology ofdirect communication between terminals. A difference from the existingcellular communications technology is that, data of user equipment doesnot need to be transmitted by a base station, but is transmitteddirectly by using an air interface between terminals, thereby reducing adelay of network forwarding. A typical application scenario is a publicsafety scenario, for example, communication between members of a firealarm group.

A resource used by traditional user equipment for transmitting data maybe scheduled by a base station in a cellular network. That is, the userequipment reports, to the base station by using a buffer status report(BSR), an amount of data waiting to be sent, and the base stationschedules a data resource according to the BSR.

However, a D2D device may belong to multiple communications groups atthe same time, for example, a device may belong to both a fire alarmgroup and a police group. When a D2D device needs to report bufferstatus reports of multiple different communications groups, atraditional BSR mechanism cannot be applied to a case in which there aremultiple communications groups. That is, in the existing BSR mechanism,to-be-transmitted buffer data of multiple communications groups cannotbe reported, and therefore a base station cannot schedule a resource forthe D2D device.

SUMMARY

In view of this, embodiments of the present invention provide acommunications method, which is used for a BSR mechanism between a D2Ddevice and a base station, so as to implement resource scheduling fordifferent communications groups.

According to an embodiment of the present invention, user equipment UEis provided, where the UE is a device-to-device D2D device, the UEbelongs to at least one communications group, each communications groupis corresponding to at least one logical channel group, and the UEincludes: a processing unit, configured to determine identificationinformation of a currently-enabled communications group; and configuredto generate information about an amount of to-be-transmitted data, wherethe information about the amount of the to-be-transmitted data includesthe identification information of the currently-enabled communicationsgroup, and a buffer status report of a logical channel groupcorresponding to the currently-enabled communications group, and theamount of the to-be-transmitted data is an amount of data to betransmitted between the UE and another D2D device in thecurrently-enabled communications group; a sending unit, configured tosend the information about the amount of the to-be-transmitted data to abase station; and a receiving unit, configured to receive informationthat is about a resource and sent by the base station, where theresource is allocated by the base station for the currently-enabledcommunications group, and the information about the resource includesthe identification information of the currently-enabled communicationsgroup, where the sending unit is further configured to transmit data inthe currently-enabled communications group by using the resource.

Optionally, the identification information of the currently-enabledcommunications group includes an index number of the currently-enabledcommunications group.

Optionally, the index number of the currently-enabled communicationsgroup is obtained according to a sequence, in a list, of theidentification information of the currently-enabled communicationsgroup, and the list includes identification information of all thecurrently-enabled communications groups.

Optionally, the sending unit is further configured to send the list tothe base station.

Optionally, that the sending unit is configured to send the informationabout the amount of the to-be-transmitted data to the base stationincludes: sending at least one MAC control element to the base station,where each MAC control element includes information about an amount ofto-be-transmitted data of one of the currently-enabled communicationsgroups.

Optionally, that the sending unit is configured to send the informationabout the amount of the to-be-transmitted data to the base stationincludes: sending one Media Access Control MAC control element to thebase station, where the MAC control element includes the informationabout the amount of the to-be-transmitted data of the currently-enabledcommunications group that has data to be sent.

Optionally, that the processing unit is configured to generate theinformation about the amount of the to-be-transmitted data includes:

when there is only one currently-enabled communications group,generating information about an amount of to-be-transmitted data, wherethe information about the amount of the to-be-transmitted data does notinclude identification information of the currently-enabledcommunications group, but includes a buffer status report of a logicalchannel group corresponding to the currently-enabled communicationsgroup; and/or

when there are at least two currently-enabled communications groups,generating information about an amount of to-be-transmitted data, wherethe information about the amount of the to-be-transmitted data includesidentification information of the currently-enabled communicationsgroups, and buffer status reports of logical channel groupscorresponding to the currently-enabled communications groups, and theamount of the to-be-transmitted data is an amount of data to betransmitted between the UE and other D2D devices in thecurrently-enabled communications groups.

Optionally, before the UE generates the information about the amount ofthe to-be-transmitted data, the processing unit is further configuredto: when it is determined that a buffer of at least one of thecurrently-enabled communications groups changes from a state of havingno data waiting to be sent to a state of having data waiting to be sent,control the UE to enter a BSR triggering state; or further configuredto: when it is determined that a buffer of at least one of thecurrently-enabled communications groups changes from a state of havingno data waiting to be sent to a state of having data waiting to be sent,and a priority of the communications group is higher than a priority ofanother communications group that has data waiting to be sent, controlthe UE to enter a triggering state.

Optionally, the identification information of the currently-enabledcommunications group includes an identifier of the logical channel groupcorresponding to the currently-enabled communications group; and

the information about the amount of the to-be-transmitted data includesthe identifier of the logical channel group of the currently-enabledcommunications group, and the buffer status report of the logicalchannel group corresponding to the currently-enabled communicationsgroup.

Optionally, that the sending unit is configured to send the informationabout the amount of the to-be-transmitted data to the base stationincludes: sending one MAC control element to the base station, where theMAC control element includes information about an amount ofto-be-transmitted data of a logical channel group that has data to besent.

Optionally, identifiers of logical channel groups corresponding todifferent communications groups are different, and identifiers ofdifferent logical channel groups of a same communications group aredifferent.

According to an embodiment of the present invention, a base station isprovided and configured to communicate with user equipment UE, where theuser equipment is a device-to-device D2D device, the UE belongs to atleast one communications group, each communications group iscorresponding to at least one logical channel group, and the basestation includes: a receiving unit, configured to receive informationthat is about an amount of to-be-transmitted data and sent by the UE,where the information about the amount of the to-be-transmitted dataincludes identification information of a currently-enabledcommunications group, and a buffer status report of a logical channelgroup corresponding to the currently-enabled communications group, andthe amount of the to-be-transmitted data is an amount of data to betransmitted between the UE and another D2D device in thecurrently-enabled communications group; a processing unit, configured toallocate a resource to the UE according to the information about theamount of the to-be-transmitted data, where the resource is allocatedfor the currently-enabled communications group, and send informationabout the resource to the UE by using a sending unit, where theinformation includes the identification information of thecurrently-enabled communications group; and the sending unit, configuredto send the information about the resource to the UE.

Optionally, the identification information of the currently-enabledcommunications group includes an index number of the currently-enabledcommunications group.

Optionally, the index number of the currently-enabled communicationsgroup is obtained according to a sequence, in a list, of theidentification information of the currently-enabled communicationsgroup, and the list includes identification information of all thecurrently-enabled communications groups.

Optionally, the receiving unit is further configured to receive thelist.

Optionally, that the receiving unit is configured to receive theinformation that is about the amount of the to-be-transmitted data andsent by the UE includes: receiving at least one Media Access Control MACcontrol element, where each MAC control element includes informationabout an amount of to-be-transmitted data of one of thecurrently-enabled communications groups.

Optionally, that the receiving unit is configured to receive theinformation that is about the amount of the to-be-transmitted data andsent by the UE includes: receiving one MAC control element, where theMAC control element includes the information about the amount of theto-be-transmitted data of the currently-enabled communications groupthat has data to be sent.

Optionally, the identification information of the currently-enabledcommunications group includes an identifier of the logical channel groupcorresponding to the currently-enabled communications group; and theinformation about the amount of the to-be-transmitted data includes theidentifier of the logical channel group of the currently-enabledcommunications group, and the buffer status report of the logicalchannel group of the currently-enabled communications group.

Optionally, that the receiving unit is configured to receive theinformation that is about the amount of the to-be-transmitted data andsent by the UE includes: receiving one MAC control element, where theMAC control element includes information about an amount ofto-be-transmitted data of a logical channel group that has data to besent.

Optionally, identifiers of logical channel groups corresponding todifferent communications groups are different, and identifiers ofdifferent logical channel groups of a same communications group aredifferent.

According to an embodiment of the present invention, a communicationsmethod is provided, where user equipment UE is a device-to-device D2Ddevice, the UE belongs to at least one communications group, eachcommunications group is corresponding to at least one logical channelgroup, and the method includes the following steps: determining, by theUE, identification information of a currently-enabled communicationsgroup; generating, by the UE, information about an amount ofto-be-transmitted data, where the information about the amount of theto-be-transmitted data includes the identification information of thecurrently-enabled communications group, and a buffer status report of alogical channel group corresponding to the currently-enabledcommunications group, and the amount of the to-be-transmitted data is anamount of data to be transmitted between the UE and another D2D devicein the currently-enabled communications group; sending, by the UE, theinformation about the amount of the to-be-transmitted data to a basestation; receiving, by the UE, information about a resource, where theresource is allocated by the base station for the currently-enabledcommunications group, and the information about the resource includesthe identification information of the currently-enabled communicationsgroup; and transmitting, by the UE, data in the currently-enabledcommunications group by using the resource.

Optionally, the identification information of the currently-enabledcommunications group includes an index number of the currently-enabledcommunications group.

Optionally, the index number of the currently-enabled communicationsgroup is obtained according to a sequence, in a list, of theidentification information of the currently-enabled communicationsgroup, and the list includes identification information of all thecurrently-enabled communications groups.

Optionally, the method includes: sending the list to the base station.

Optionally, the sending, by the UE, the information about the amount ofthe to-be-transmitted data to a base station is specifically: sending,by the UE, at least one Media Access Control MAC control element to thebase station, where each MAC control element includes information aboutan amount of to-be-transmitted data of one of the currently-enabledcommunications groups.

Optionally, the sending, by the UE, the information about the amount ofthe to-be-transmitted data to a base station is specifically: sending,by the UE, one MAC control element to the base station, where the MACcontrol element includes the information about the amount of theto-be-transmitted data of the currently-enabled communications groupthat has data to be sent.

Optionally, when there is only one currently-enabled communicationsgroup, the information that is about the amount of the to-be-transmitteddata and generated by the UE does not include identification informationof the currently-enabled communications group, but includes a bufferstatus report of a logical channel group corresponding to thecurrently-enabled communications group; and/or when there are at leasttwo currently-enabled communications groups, information about an amountof to-be-transmitted data is generated, where the information about theamount of the to-be-transmitted data includes identification informationof the currently-enabled communications groups, and buffer statusreports of logical channel groups corresponding to the currently-enabledcommunications groups, and the amount of the to-be-transmitted data isan amount of data to be transmitted between the UE and other D2D devicesin the currently-enabled communications groups.

Optionally, before the generating, by the UE, information about anamount of to-be-transmitted data, the method includes: when it isdetermined that a buffer of at least one of the currently-enabledcommunications groups changes from a state of having no data waiting tobe sent to a state of having data waiting to be sent, entering, by theUE, a triggering state; or when it is determined that a buffer of atleast one of the currently-enabled communications groups changes from astate of having no data waiting to be sent to a state of having datawaiting to be sent, and a priority of the communications group is higherthan a priority of another communications group that has data waiting tobe sent, entering, by the UE, a triggering state.

Optionally, the identification information of the currently-enabledcommunications group includes an identifier of the logical channel groupcorresponding to the currently-enabled communications group; and theinformation about the amount of the to-be-transmitted data includes theidentifier of the logical channel group of the currently-enabledcommunications group, and the buffer status report of the logicalchannel group corresponding to the currently-enabled communicationsgroup.

Optionally, the sending the information about the amount of theto-be-transmitted data to a base station is specifically:

sending, by the UE, one MAC control element to the base station, wherethe MAC control element includes information about an amount ofto-be-transmitted data of a logical channel group that has data to besent.

Optionally, identifiers of logical channel groups corresponding todifferent communications groups are different, and identifiers ofdifferent logical channel groups of a same communications group aredifferent.

According to an embodiment of the present invention, a communicationsmethod is provided and used for communication with user equipment UE,where the user equipment UE is a device-to-device D2D device, the UEbelongs to at least one communications group, each communications groupis corresponding to at least one logical channel group, and the methodincludes the following steps: receiving, by a base station, informationthat is about an amount of to-be-transmitted data and sent by the UE,where the information about the amount of the to-be-transmitted dataincludes identification information of a currently-enabledcommunications group, and a buffer status report of a logical channelgroup corresponding to the currently-enabled communications group, andthe amount of the to-be-transmitted data is an amount of data to betransmitted between the UE and another D2D device in thecurrently-enabled communications group; allocating, by the base station,a resource to the UE according to the information about the amount ofthe to-be-transmitted data, where the resource is allocated for thecurrently-enabled communications group, and sending information aboutthe resource to the UE by using a sending unit, where the informationincludes the identification information of the currently-enabledcommunications group; and sending, by the base station, the informationabout the resource to the UE.

Optionally, the identification information of the currently-enabledcommunications group includes an index number of the currently-enabledcommunications group.

Optionally, the index number of the currently-enabled communicationsgroup is obtained according to a sequence, in a list, of theidentification information of the currently-enabled communicationsgroup, and the list includes identification information of all thecurrently-enabled communications groups.

Optionally, the method includes: receiving, by the base station, thelist.

Optionally, the receiving, by a base station, information that is aboutan amount of to-be-transmitted data and sent by the UE is specifically:receiving, by the base station, at least one Media Access Control MACcontrol element, where each MAC control element includes informationabout an amount of to-be-transmitted data of one of thecurrently-enabled communications groups.

Optionally, the receiving, by a base station, information that is aboutan amount of to-be-transmitted data and sent by the UE is specifically:receiving, by the base station, one MAC control element, where the MACcontrol element includes the information about the amount of theto-be-transmitted data of the currently-enabled communications groupthat has data to be sent.

Optionally, the identification information of the currently-enabledcommunications group includes an identifier of the logical channel groupcorresponding to the currently-enabled communications group; and theinformation about the amount of the to-be-transmitted data includes theidentifier of the logical channel group of the currently-enabledcommunications group, and the buffer status report of the logicalchannel group of the currently-enabled communications group.

Optionally, the receiving, by a base station, information that is aboutan amount of to-be-transmitted data and sent by the UE is specifically:receiving, by the base station, one MAC control element, where the MACcontrol element includes information about an amount ofto-be-transmitted data of a logical channel group that has data to besent.

Optionally, identifiers of logical channel groups corresponding todifferent communications groups are different, and identifiers ofdifferent logical channel groups of a same communications group aredifferent.

According to an embodiment of the present invention, user equipment UEis provided, where the UE is a device-to-device D2D device, the UEbelongs to at least one communications group, each communications groupis corresponding to at least one logical channel group, and the UEincludes: a processor, configured to determine identificationinformation of a currently-enabled communications group; and configuredto generate information about an amount of to-be-transmitted data, wherethe information about the amount of the to-be-transmitted data includesthe identification information of the currently-enabled communicationsgroup, and a buffer status report of a logical channel groupcorresponding to the currently-enabled communications group, and theamount of the to-be-transmitted data is an amount of data to betransmitted between the UE and another D2D device in thecurrently-enabled communications group; a sender, configured to send theinformation about the amount of the to-be-transmitted data to a basestation; and a receiver, configured to receive information that is abouta resource and sent by the base station, where the resource is allocatedby the base station for the currently-enabled communications group, andthe information about the resource includes the identificationinformation of the currently-enabled communications group, where thesender is further configured to transmit data in the currently-enabledcommunications group by using the resource.

According to an embodiment of the present invention, a base station isprovided and configured to communicate with user equipment UE, where theuser equipment is a device-to-device D2D device, the UE belongs to atleast one communications group, each communications group iscorresponding to at least one logical channel group, and the basestation includes: a receiver, configured to receive information that isabout an amount of to-be-transmitted data and sent by the UE, where theinformation about the amount of the to-be-transmitted data includesidentification information of a currently-enabled communications group,and a buffer status report of a logical channel group corresponding tothe currently-enabled communications group, and the amount of theto-be-transmitted data is an amount of data to be transmitted betweenthe UE and another D2D device in the currently-enabled communicationsgroup; a processor, configured to allocate a resource to the UEaccording to the information about the amount of the to-be-transmitteddata, where the resource is allocated for the currently-enabledcommunications group, and send information about the resource to the UEby using a sender, where the information includes the identificationinformation of the currently-enabled communications group; and thesender, configured to send the information about the resource to the UE.

In the foregoing solution, a UE may determine identification informationof a currently-enabled communications group, generate information aboutan amount of to-be-transmitted data, and send the information about theamount of the to-be-transmitted data to a base station, where theinformation about the amount of the to-be-transmitted data includes theidentification information of the currently-enabled communicationsgroup, so that the base station can distinguish between differentcommunications groups, and separately schedule resources for data of thecommunications groups.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a solution in which a BSR is reported for uplink datatransmission in an LTE network;

FIG. 2 shows an implementation solution according to an embodiment ofthe present invention;

FIG. 3 shows another implementation solution according to an embodimentof the present invention;

FIG. 4 shows another implementation solution according to an embodimentof the present invention;

FIG. 5 shows another implementation solution according to an embodimentof the present invention;

FIG. 6 shows a method according to an embodiment of the presentinvention;

FIG. 7 shows a UE according to an embodiment of the present invention;

FIG. 8 shows a base station according to an embodiment of the presentinvention;

FIG. 9 shows another UE according to an embodiment of the presentinvention; and

FIG. 10 shows another base station according to an embodiment of thepresent invention.

DESCRIPTION OF EMBODIMENTS

To make the objectives, technical solutions, and advantages ofembodiments of the present invention clearer, the following furtherdescribes the embodiments of the present invention in detail withreference to the accompanying drawings.

An embodiment of the present invention provides a communications method,which can be applied to a D2D device and a base station of the D2Ddevice. A base station in the present invention is not limited to in ascenario of an evolved NodeB (eNB), and may be in another scenario. Inpractice, the base station may be a base station of another technology,such as a Universal Mobile Telecommunications System (UMTS), a GlobalSystem for Mobile Communications (GSM), or a Worldwide Interoperabilityfor Microwave Access (WiMAX).

In a Long Term Evolution (LTE) network, user equipment (UE) reports, toa base station by using a BSR, an amount of data that is buffered in anuplink buffer and waits to be sent. Information about the amount of theto-be-transmitted data includes a BSR of a logical channel group. In theLTE network, a target to which the UE sends data is only the basestation, and therefore the BSR needs to include only the informationabout the amount of the to-be-transmitted data sent to the base station.FIG. 1 shows a solution in which a BSR is reported for uplink datatransmission in an LTE network. Each Oct represents one byte, including8 bits. In this solution, four logical channel groups are included, anda BSR of each logical channel group occupies 6 bits, for example, BufferSize #0 of logical channel group #0 occupies 6 bits.

In D2D communications, one UE may belong to multiple communicationsgroups at the same time, for example, one UE may belong to both a firealarm group and a police group. Each communications group is furthercorresponding to multiple different logical channel groups. Data thatwaits to be sent to multiple communications groups may exist in a bufferof the UE at the same time. Therefore, the BSR shown in FIG. 1 cannotmeet the foregoing requirement.

In the embodiments of the present invention, the foregoing problem canbe solved by adding an identifier of a communications group toinformation about an amount of to-be-transmitted data in a D2D scenario.

FIG. 2 shows an implementation solution according to an embodiment ofthe present invention. In this solution, a UE may belong to differentcommunications groups, and multiple communications groups may becurrently enabled for communication. In the embodiment shown in FIG. 2,information that is about an amount of to-be-transmitted data andreported by the UE includes an identifier of a currently-enabledcommunications group (ProSe Group Identifier). The ProSe is anabbreviation of proximity service (proximity service). As shown in FIG.2, the identifier of the communications group occupies 6 bytes, that is,48 bits in total. The information about the amount of theto-be-transmitted data further includes buffer status reports of logicalchannel groups corresponding to the currently-enabled communicationsgroup. Each buffer status report identifies an amount of data to betransmitted between the UE and another D2D device in thecurrently-enabled communications group. Buffer Size #0 indicates anamount of data waiting to be transmitted by the UE in logical channelgroup #0 corresponding to the communications group. There are totallyfour such buffer status reports, which are respectively Buffer Size #0,Buffer Size #1, Buffer Size #2, and Buffer Size #3. Each buffer statusreport occupies 6 bits, and the buffer status reports are successivelyconcatenated.

As shown in FIG. 6, a method embodiment of the present inventionincludes the following steps:

101. A UE determines identification information of a currently-enabledcommunications group.

The identification information of the communications group may include aunique identifier of the communications group. The unique identifier mayuniquely identify the communications group in an entire network.

102. The UE generates information about an amount of to-be-transmitteddata, where the information about the amount of the to-be-transmitteddata includes the identification information of the currently-enabledcommunications group, and a buffer status report of a logical channelgroup corresponding to the currently-enabled communications group, andthe amount of the to-be-transmitted data is an amount of data to betransmitted between the UE and another D2D device in thecurrently-enabled communications group.

103. The UE sends the information about the amount of theto-be-transmitted data to a base station.

104. The base station receives the information that is about the amountof the to-be-transmitted data and sent by the UE.

105. The base station allocates a resource to the UE according to theinformation about the amount of the to-be-transmitted data, where theresource is allocated for the currently-enabled communications group.

For example, in the embodiment in FIG. 2, a base station allocates,according to an identifier of a communications group (ProSe GroupIdentifier) and amounts of to-be-transmitted data indicated by bufferstatus reports Buffer Size #0, Buffer Size #1, Buffer Size #2, andBuffer Size #3 corresponding to the communications group, correspondingresources to logical channel groups corresponding to these buffer statusreports in the communications group.

106. The base station sends, to the UE, information about the resourceallocated to the UE. The information about the resource includes anidentifier of the currently-enabled communications group. In addition tothe identifier of the communications group, the information about theresource may include the resource allocated to the UE.

The UE receives the information about the resource, where theinformation about the resource includes the identifier of thecurrently-enabled communications group and the resource allocated to theUE. The UE transmits data corresponding to the currently-enabledcommunications group by using the resource.

It may be learned that, in this embodiment of the present invention,identifiers of different communications groups and buffer status reportsof logical channel groups corresponding to the communications groups aretransmitted to a base station, and the base station can distinguishbetween different communications groups and further schedule resourcesfor the different communications groups.

An identifier of a communications group (ProSe Group Identifier) in FIG.2 occupies 48 bits, which increases a signaling overhead in a system. InFIG. 3, the identifier of the communications group is replaced with anindex number of the communications group (ProSe Group Index). For a UE,the UE needs to determine an index number corresponding to a uniqueidentifier of a communications group; for a base station, the basestation needs to obtain the unique identifier of the communicationsgroup according to a received index number by means of table lookup andthe like. An index number of a currently-enabled communications groupoccupies relatively less bytes. In FIG. 3, one byte is used as anexample, and it may be understood that a length of the index number maybe another length.

In the embodiment in FIG. 3, an index number of one communications groupand buffer status reports of logical channel groups corresponding to thecommunications group form information about an amount ofto-be-transmitted data of the communications group. When sending theinformation about the amount of the to-be-transmitted data of thecommunications group, a UE may use the information about the amount ofthe to-be-transmitted data of the communications group as one MediaAccess Control (MAC) control element for sending. Differentcommunications groups use different MAC control elements for sending. Abase station obtains identifiers of corresponding communications groupsand buffer status reports of corresponding logical channel groups byusing the different MAC control elements.

It may be understood that the identification information of thecommunications group is not limited to the identifier of thecommunications group and the index number of the communications group,and may further include another piece of information that can identifythe communications group.

It may be learned that in addition to having advantages of theembodiment in FIG. 2, the embodiment in FIG. 3 saves a signalingresource.

For a solution in which an index number is used in the foregoingembodiment, an embodiment of the present invention provides a specificimplementation solution.

Firstly, a UE reports, to a base station, a list of currently-enabledcommunications groups to which the UE belongs, where the list includesunique identifiers of all the currently-enabled communications groups,such as {an identifier of communications group A, an identifier ofcommunications group B, and an identifier of communications group C};the list may further include priority information corresponding to allthe currently-enabled communications groups, where the priorityinformation indicates a transmission priority of the communicationsgroups.

Secondly, the UE may acquire index numbers corresponding to thecommunications groups according to a sequence of the communicationsgroups in the list. For example, the first element in the foregoing listis communications group A, and an index number corresponding tocommunications group A is 1; the second element is communications groupB, and an index number corresponding to communications group B is 2.

Thirdly, the UE generates information about an amount ofto-be-transmitted data according to the foregoing index numbers, andsends the information to the base station.

Fourthly, the base station determines the unique identifiers of thecurrently-enabled communications groups according to the index numbersincluded in the received information about the amount of theto-be-transmitted data and the list, and allocates resources to thecommunications groups corresponding to the unique identifiers.

The UE transmits data on specified resources according to informationabout the allocated resources. A process is the same as that of atechnical solution in FIG. 2, and details are not described herein.

It should be noted that the list that is of the communications groupsand is used by the base station may be reported by the UE, or may beobtained by using another means. For example, the base station maypreset the list of the communications groups, or another device notifiesthe base station of the list of the communications groups.Correspondingly, the UE may send the list to the base station before theUE generates the information about the amount of the to-be-transmitteddata, or after the UE generates the information about the amount of theto-be-transmitted data.

It may be learned that the foregoing embodiment in which an index numberand a list are used provides another implementation manner, whichimproves flexibility of a technical solution, and the solution furtherhas the following advantages: A UE determines an index number by using aset list, which can prevent directly adding identification informationof a communications group into information about an amount ofto-be-transmitted data when the information about the amount of theto-be-transmitted data is being sent. Therefore, a signaling resourcecan be saved, and the information about the amount of theto-be-transmitted data can carry more BSR information.

FIG. 4 shows another embodiment of the present invention. An indexnumber of one communications group and buffer status reports of logicalchannel groups corresponding to the communications group forminformation about an amount of to-be-transmitted data of thecommunications group. When sending the information about the amount ofthe to-be-transmitted data of the communications group, a UE maysuccessively concatenate multiple pieces of the information about theamount of the to-be-transmitted data as one MAC control element forsending. A base station obtains identifiers of different communicationsgroups and buffer status reports of logical channel groups correspondingto the communications groups by using the MAC control element.

It should be noted that if the concatenated control element has too manycommunications groups or too many logical channel groups, the controlelement may be divided into multiple control elements that are thenseparately sent to the base station. Each control element obtained bymeans of division includes one header. Division of the control elementmay be specifically performed according to a channel condition, forexample, division is performed according to a size of an uplink resourceallocated by the base station.

It may be learned that, in the embodiment in FIG. 4, more MAC controlelements are not needed, and therefore only less MAC headers need to besent. Therefore, in addition to having advantages of the foregoingembodiments, the embodiment in FIG. 4 reduces headers and further savesa signaling resource.

According to another embodiment of the present invention, a solution isas follows:

Before generating information about an amount of to-be-transmitted data,a UE determines whether there is only one currently-enabledcommunications group:

When there is only one currently-enabled communications group,information that is about an amount of to-be-transmitted data andgenerated by the UE does not include identification information of thecurrently-enabled communications group, but includes a buffer statusreport of a logical channel group corresponding to the currently-enabledcommunications group. For example, in the scenario in FIG. 2, if thereis only one currently-enabled communications group, the UE does not needto send the ProSe Group Identifier. A corresponding base station may notneed an identifier of the communications group either, and may directlyallocate a resource for the logical channel group. It may be learnedthat in such a solution, an identifier of a communications group doesnot need to be transmitted, which saves a signaling overhead.

When there are at least two currently-enabled communications groups,information about an amount of to-be-transmitted data is generated,where the information about the amount of the to-be-transmitted dataincludes identification information of the currently-enabledcommunications groups, and buffer status reports of logical channelgroups corresponding to the currently-enabled communications groups, andthe amount of the to-be-transmitted data is an amount of data to betransmitted between the UE and other D2D devices in thecurrently-enabled communications groups.

After the information about the amount of the to-be-transmitted data isgenerated, for a subsequent implementation solution, refer to theforegoing embodiments, and details are not described herein again.

According to another embodiment of the present invention, a solution isas follows:

Before generating information about an amount of to-be-transmitted data,a UE enters a triggering state. A process of entering the triggeringstate may be as follows:

When it is determined that a buffer of at least one of thecurrently-enabled communications groups changes from a state of havingno data waiting to be sent to a state of having data waiting to be sent,the UE enters the triggering state; or

when it is determined that a buffer of at least one of thecurrently-enabled communications groups changes from a state of havingno data waiting to be sent to a state of having data waiting to be sent,and a priority of the communications group is higher than a priority ofanother communications group that has data waiting to be sent, the UEenters the triggering state.

The UE notifies a base station that the UE enters the triggering state,and the base station may allocate, to the UE, a resource used forreporting a buffer status report. After the UE obtains the allocatedresource, the UE generates the information about the amount of theto-be-transmitted data and performs subsequent steps. Other steps arethe same as those in the foregoing embodiments, and details are notdescribed again.

It may be learned that in addition to having advantages of theembodiment in FIG. 3, this embodiment has the following advantages: Whena UE has a new communications group that has data waiting to be sent, ora communications group that is of a higher priority and has data waitingto be sent, the UE may report information about a buffer status reportof the communications group to a base station in a timely manner, wherethe buffer status report is used by the base station to schedule data ina timely manner, thereby further accelerating data transmission.

FIG. 5 shows another embodiment of the present invention. Identificationinformation of a currently-enabled communications group may includeidentifiers of logical channel groups corresponding to thecurrently-enabled communications group. In an example in FIG. 5, theidentifiers of the logical channel groups are LCG #0, LCG #1, . . . . Alength of an identifier of each logical channel group may be 8 bits, ormay be another length. The identifier of each logical channel group isfollowed by a buffer status report of the logical channel group.Identifiers of logical channel groups corresponding to differentcommunications groups are different, and identifiers of differentlogical channel groups of a same communications group are different. Inother words, identifiers of the logical channel groups may identifycommunications groups corresponding to the logical channel groups. Inthis way, a UE or a base station may know information about thecorresponding communications groups according to the identifiers of thelogical channel groups. Identifiers of multiple logical channel groupscorresponding to a communications group and buffer status reports of thelogical channel groups corresponding to the communications group forminformation about an amount of to-be-transmitted data of one or morecommunications groups.

In addition, when sending the information about the amount of theto-be-transmitted data of the one or more communications groups, the UEmay successively concatenate the multiple pieces of information aboutthe amount of the to-be-transmitted data as one MAC control element forsending. The MAC control element includes information about an amount ofto-be-transmitted data of a logical channel group that has data to besent. The base station obtains, by using the MAC control element,identifiers of different logical channel groups and buffer statusreports that are corresponding to the MAC control element.

In addition to having advantages of the foregoing embodiments, theembodiment in FIG. 5 has the following advantages: An identifier of alogical channel group may indicate information of a communications groupcorresponding to the logical channel group, which provides anotherimplementation manner and improves flexibility of a technical solution.

It should be noted that the logical channel groups may be spaced but notconsecutive. For example, logical channel group #1 has no data to besent, and the MAC control element may successively include LCG #0 and abuffer status report of LCG #0, LCG #2 and a buffer status report of LCG#2, . . . . Because an identifier of each logical channel group and abuffer status report corresponding to each logical channel group areindicated, logical channel groups having no sequence can be successivelytransmitted, so that a signaling resource is saved.

According to an embodiment of the present invention, user equipment UEis provided, where the UE is a device-to-device D2D device, the UEbelongs to at least one communications group, each communications groupis corresponding to at least one logical channel group, and the UEincludes: a processing unit, configured to determine identificationinformation of a currently-enabled communications group; and configuredto generate information about an amount of to-be-transmitted data, wherethe information about the amount of the to-be-transmitted data includesthe identification information of the currently-enabled communicationsgroup, and a buffer status report of a logical channel groupcorresponding to the currently-enabled communications group, and theamount of the to-be-transmitted data is an amount of data to betransmitted between the UE and another D2D device in thecurrently-enabled communications group; a sending unit, configured tosend the information about the amount of the to-be-transmitted data to abase station; and a receiving unit, configured to receive informationthat is about a resource and sent by the base station, where theresource is allocated by the base station for the currently-enabledcommunications group, and the information about the resource includesthe identification information of the currently-enabled communicationsgroup, where the sending unit is further configured to transmit data inthe currently-enabled communications group by using the resource.

According to this embodiment of the present invention, theidentification information of the currently-enabled communications groupincludes an index number of the currently-enabled communications group,or includes a unique identifier of the currently-enabled communicationsgroup.

According to this embodiment of the present invention, the index numberof the currently-enabled communications group is obtained according to asequence, in a list, of the unique identifier of the currently-enabledcommunications group, and the list includes unique identifiers of allthe currently-enabled communications groups.

According to this embodiment of the present invention, the sending unitis further configured to send the list to the base station.

According to this embodiment of the present invention, that the sendingunit is configured to send the information about the amount of theto-be-transmitted data to the base station includes: sending at leastone MAC control element to the base station, where each MAC controlelement includes information about an amount of to-be-transmitted dataof one of the currently-enabled communications groups.

According to this embodiment of the present invention, that the sendingunit is configured to send the information about the amount of theto-be-transmitted data to the base station includes: sending one MediaAccess Control MAC control element to the base station, where the MACcontrol element includes the information about the amount of theto-be-transmitted data of the currently-enabled communications groupthat has data to be sent.

According to this embodiment of the present invention, that theprocessing unit is configured to generate the information about theamount of the to-be-transmitted data includes: when there is only onecurrently-enabled communications group, generating information about anamount of to-be-transmitted data, where the information about the amountof the to-be-transmitted data does not include identificationinformation of the currently-enabled communications group, but includesa buffer status report of a logical channel group corresponding to thecurrently-enabled communications group; and/or when there are at leasttwo currently-enabled communications groups, generating informationabout an amount of to-be-transmitted data, where the information aboutthe amount of the to-be-transmitted data includes identificationinformation of the currently-enabled communications groups, and bufferstatus reports of logical channel groups corresponding to thecurrently-enabled communications groups, and the amount of theto-be-transmitted data is an amount of data to be transmitted betweenthe UE and other D2D devices in the currently-enabled communicationsgroups.

According to this embodiment of the present invention, before the UEgenerates the information about the amount of the to-be-transmitteddata, the processing unit is further configured to: when it isdetermined that a buffer of at least one of the currently-enabledcommunications groups changes from a state of having no data waiting tobe sent to a state of having data waiting to be sent, control the UE toenter a BSR triggering state; or further configured to: when it isdetermined that a buffer of at least one of the currently-enabledcommunications groups changes from a state of having no data waiting tobe sent to a state of having data waiting to be sent, and a priority ofthe communications group is higher than a priority of anothercommunications group that has data waiting to be sent, control the UE toenter a triggering state.

According to this embodiment of the present invention, theidentification information of the currently-enabled communications groupincludes an identifier of the logical channel group corresponding to thecurrently-enabled communications group; and the information about theamount of the to-be-transmitted data includes the identifier of thelogical channel group of the currently-enabled communications group, andthe buffer status report of the logical channel group corresponding tothe currently-enabled communications group.

According to this embodiment of the present invention, that the sendingunit is configured to send the information about the amount of theto-be-transmitted data to the base station includes: sending one MACcontrol element to the base station, where the MAC control elementincludes information about an amount of to-be-transmitted data of alogical channel group that has data to be sent.

According to this embodiment of the present invention, identifiers oflogical channel groups corresponding to different communications groupsare different, and identifiers of different logical channel groups of asame communications group are different.

For the foregoing embodiment of the UE, this embodiment is an apparatusembodiment corresponding to the foregoing method embodiment. An effectof this apparatus embodiment is similar to that of the foregoing methodembodiment, and details are not described again.

In addition, in addition to performing operations enumerated in theforegoing apparatus embodiment, the processing unit in the UE mayperform various operations that are on a UE side except sending andreceiving operations in the foregoing method embodiment and are notenumerated in this apparatus embodiment. The sending unit and thereceiving unit in the UE may respectively send and receive informationon the UE side correspondingly according to a requirement.

According to an embodiment of the present invention, a base station isprovided and configured to communicate with user equipment UE, where theuser equipment is a device-to-device D2D device, the UE belongs to atleast one communications group, each communications group iscorresponding to at least one logical channel group, and the basestation includes: a receiving unit, configured to receive informationthat is about an amount of to-be-transmitted data and sent by the UE,where the information about the amount of the to-be-transmitted dataincludes identification information of a currently-enabledcommunications group, and a buffer status report of a logical channelgroup corresponding to the currently-enabled communications group, andthe amount of the to-be-transmitted data is an amount of data to betransmitted between the UE and another D2D device in thecurrently-enabled communications group; a processing unit, configured toallocate a resource to the UE according to the information about theamount of the to-be-transmitted data, where the resource is allocatedfor the currently-enabled communications group, and send informationabout the resource to the UE by using a sending unit, where theinformation includes the identification information of thecurrently-enabled communications group; and the sending unit, configuredto send the information about the resource to the UE.

According to this embodiment of the present invention, theidentification information of the currently-enabled communications groupincludes an index number of the currently-enabled communications group,or includes a unique identifier of the currently-enabled communicationsgroup.

According to this embodiment of the present invention, the index numberof the currently-enabled communications group is obtained according to asequence, in a list, of the unique identifier of the currently-enabledcommunications group, and the list includes unique identifiers of allthe currently-enabled communications groups.

Correspondingly, that the processing unit is configured to allocate theresource to the UE according to the information about the amount of theto-be-transmitted data includes: determining the unique identifier ofthe currently-enabled communications group according to the index numberreceived by the receiving unit and the list, and allocating a resourceto the communications group corresponding to information about theunique identifier.

According to this embodiment of the present invention, the receivingunit is further configured to receive the list.

According to this embodiment of the present invention, that thereceiving unit is configured to receive the information that is aboutthe amount of the to-be-transmitted data and sent by the UE includes:receiving at least one Media Access Control MAC control element, whereeach MAC control element includes information about an amount ofto-be-transmitted data of one of the currently-enabled communicationsgroups.

According to this embodiment of the present invention, that thereceiving unit is configured to receive the information that is aboutthe amount of the to-be-transmitted data and sent by the UE includes:receiving one MAC control element, where the MAC control elementincludes the information about the amount of the to-be-transmitted dataof the currently-enabled communications group that has data to be sent.

According to this embodiment of the present invention, theidentification information of the currently-enabled communications groupincludes an identifier of the logical channel group corresponding to thecurrently-enabled communications group; and

the information about the amount of the to-be-transmitted data includesthe identifier of the logical channel group of the currently-enabledcommunications group, and the buffer status report of the logicalchannel group of the currently-enabled communications group.

According to this embodiment of the present invention, that thereceiving unit is configured to receive the information that is aboutthe amount of the to-be-transmitted data and sent by the UE includes:receiving one MAC control element, where the MAC control elementincludes information about an amount of to-be-transmitted data of alogical channel group that has data to be sent.

According to this embodiment of the present invention, identifiers oflogical channel groups corresponding to different communications groupsare different, and identifiers of different logical channel groups of asame communications group are different.

For the foregoing embodiment of the base station, this embodiment is anapparatus embodiment corresponding to the foregoing method embodiment.An effect of this apparatus embodiment is similar to that of theforegoing method embodiment, and details are not described again.

In addition, in addition to performing operations enumerated in theforegoing base station apparatus embodiment, the processing unit in thebase station may perform various operations that are on a base stationside except sending and receiving operations in the foregoing methodembodiment and are not enumerated in the base station apparatusembodiment. The sending unit and the receiving unit in the base stationmay respectively send and receive information on the base station sidecorrespondingly according to a requirement.

According to an embodiment of the present invention, another userequipment UE is further provided, where the UE is a device-to-device D2Ddevice, the UE belongs to at least one communications group, eachcommunications group is corresponding to at least one logical channelgroup, and the UE includes: a processor, a receiver, and a sender. Theprocessor in this embodiment is similar to the processing unit in the UEin the foregoing embodiment and can complete a same function. The senderis similar to the sending unit in the UE in the foregoing embodiment andcan complete a same function. The receiver is similar to the receivingunit in the UE in the foregoing embodiment and can complete a samefunction. A connection relationship of the processor, the sender, andthe receiver is consistent with a connection relationship of theforegoing processing unit, sending unit, and receiving unit, and is usedto solve a same technical problem and obtain a same technical effect,and details are not described herein again.

According to an embodiment of the present invention, another basestation is further provided and configured to communicate with userequipment UE, where the user equipment is a device-to-device D2D device,the UE belongs to at least one communications group, each communicationsgroup is corresponding to at least one logical channel group, and thebase station includes: a receiver, a processor, and a sender. Theprocessor in this embodiment is similar to the processing unit in thebase station in the foregoing embodiment and can complete a samefunction. The sender is similar to the sending unit in the base stationin the foregoing embodiment and can complete a same function. Thereceiver is similar to the receiving unit in the base station in theforegoing embodiment and can complete a same function. A connectionrelationship of the processor, the sender, and the receiver isconsistent with a connection relationship of the foregoing processingunit, sending unit, and receiving unit, and is used to solve a sametechnical problem and obtain a same technical effect, and details arenot described herein again.

Effect of the foregoing another UE and base station are similar to thosein the foregoing method embodiments, and details are not describedagain. The steps in the foregoing methods may be completed by using anintegrated logic circuit of hardware in the processor or instructions ina form of software. These instructions may be implemented and controlledby working with the processor in the foregoing methods. Configured toexecute the methods disclosed in the embodiments of the presentinvention, the foregoing processor may be a general purpose processor, adigital signal processor (DSP), an application-specific integratedcircuit (ASIC), a field programmable gate array (FPGA), or anotherprogrammable logical device, discrete gate or transistor logical device,or discrete hardware component. The processor may implement or executemethods, steps and logical block diagrams disclosed in the embodimentsof the present invention. A general purpose processor may be amicroprocessor or the processor may also be any conventional processor,decoder, and the like. Steps of the methods disclosed with reference tothe embodiments of the present invention may be directly executed andaccomplished by means of a hardware processor, or may be executed andcompleted by using a combination of hardware and software modules in theprocessor. The software module may be located in a mature storage mediumin the field, such as a random access memory, a flash memory, aread-only memory, a programmable read-only memory, anelectrically-erasable programmable memory, or a register. The storagemedium is located in the memory, and the processor reads information inthe memory and completes the steps in the foregoing methods incombination with hardware of the processor.

With descriptions of the foregoing embodiments, a person skilled in theart may clearly understand that the present invention may be implementedby hardware, firmware or a combination thereof. When the presentinvention is implemented by software, the foregoing functions may bestored in a computer-readable medium or transmitted as one or moreinstructions or code in the computer-readable medium. Thecomputer-readable medium includes a computer storage medium and acommunications medium, where the communications medium includes anymedium that enables a computer program to be transmitted from one placeto another. The storage medium may be any available medium accessible toa computer. The following provides an example but does not impose alimitation: The computer-readable medium may include a RAM, a ROM, anEEPROM, a CD-ROM, or another optical disc storage or disk storagemedium, or another magnetic storage device, or any other medium that cancarry or store expected program code in a form of an instruction or adata structure and can be accessed by a computer. In addition, anyconnection may be appropriately defined as a computer-readable medium.For example, if software is transmitted from a website, a server oranother remote source by using a coaxial cable, an optical fiber/cable,a twisted pair, a digital subscriber line (DSL) or wireless technologiessuch as infrared ray, radio and microwave, the coaxial cable, opticalfiber/cable, twisted pair, DSL or wireless technologies such as infraredray, radio and microwave are included in fixation of a medium to whichthey belong. For example, a disk and disc used by the present inventionincludes a compact disc CD, a laser disc, an optical disc, a digitalversatile disc (DVD), a floppy disk and a Blu-ray disc, where the diskgenerally copies data by a magnetic means, and the disc copies dataoptically by a laser means. The foregoing combination should also beincluded in the protection scope of the computer-readable medium.

In summary, what is described above is merely exemplary embodiments ofthe technical solutions of the present invention, but is not intended tolimit the protection scope of the present invention. Any modification,equivalent replacement, or improvement made without departing from thespirit and principle of the present invention shall fall within theprotection scope of the present invention.

What is claimed is:
 1. A communications method, comprising: determining,by a terminal device, identification information of a communicationsgroup including the terminal device and corresponding to a logicalchannel group; generating, by the terminal device, transmissioninformation about an amount of to-be-transmitted data, the transmissioninformation including the identification information of thecommunications group, and a buffer status report of the logical channelgroup corresponding to the communications group, wherein the bufferstatus report indicates the amount of the to-be-transmitted data waitingto be transmitted in the logical channel group between the terminaldevice and another terminal device; and sending, by the terminal device,the transmission information to a base station.
 2. The method accordingto claim 1, further comprises: receiving, by the terminal device fromthe base station, resource information about a resource allocated by thebase station for the communications group, the resource informationincluding the identification information of the communications group;and transmitting, by the terminal device, communication data in thecommunications group by using the resource.
 3. The method according toclaim 2, wherein the sending of the transmission information by theterminal device to the base station comprises: sending one MAC controlelement including the transmission information of the communicationsgroup that has communication data to be sent.
 4. The method according toclaim 1, wherein the identification information of the communicationsgroup is a group identifier for proximity service (ProSe).
 5. The methodaccording to claim 1, wherein the buffer status report includes a buffersize.
 6. The method according to claim 5, wherein the buffer statusreport only provides the buffer size.
 7. The method according to claim1, wherein: the identification information of the communications groupcomprises an index number of the communications group.
 8. The methodaccording to claim 1, the method further comprises: entering, by theterminal device, a triggering state upon determination that a buffer ofa communications group has changed from a state of having no datawaiting to be sent to a state of having data waiting to be sent.
 9. Thecommunications method according to claim 1, wherein the communicationsgroup is a first communications group, the logical channel group is thefirst logical channel group, and the method further comprises:determining, by the terminal device, identification information of asecond communications group including the terminal device andcorresponding to a second logical channel group; and, wherein thetransmission information further includes the identification informationof the second communications group, and a buffer status report of thesecond logical channel group corresponding to the communications group.10. A communications method, comprising: receiving, by a network devicefrom a terminal device, transmission information about an amount ofto-be-transmitted data, the transmission information includingidentification information of a communications group that includes theterminal device, and a buffer status report of a logical channel groupcorresponding to the communications group, wherein the buffer statusreport indicates the amount of the to-be-transmitted data waiting to betransmitted in the logical channel group between the terminal device andanother terminal device; allocating, by the network device, a resourceto the terminal device in response to the transmission information; andsending resource information about the resource to the terminal deviceby the network device, the resource information including theidentification information of the communications group.
 11. The methodaccording to claim 10, wherein the identification information of thecommunications group is a group identifier for proximity service(ProSe).
 12. The method according to claim 10, wherein the buffer statusreport includes a buffer size.
 13. The method according to claim 10,wherein: the identification information of the communications groupincludes an index number of the communications group.
 14. The methodaccording to claim 10, wherein the receiving comprises: receiving, bythe network device, one MAC control element including the transmissioninformation of the communications group that has communication data tobe sent.
 15. The communications method according to claim 10, whereinthe communications group is a first communications group, the logicalchannel group is the first logical channel group; and, wherein thetransmission information about an amount of to-be-transmitted datafurther includes identification information of a second communicationsgroup that includes the terminal device, and a buffer status report of asecond logical channel group corresponding to the second communicationsgroup; and the resource information further includes informationindicating a resource allocated to the terminal device for the secondcommunications group.
 16. A communication device communicating with abase station, comprising: a processor; and a non-transitory memoryconfigured to store an execution instruction that when executed by theprocessor causes the device to determine identification information of acommunications group including the communication device andcorresponding to a logical channel group; generate transmissioninformation about an amount of to-be-transmitted data, the transmissioninformation including the identification information of thecommunications group, and a buffer status report of the logical channelgroup corresponding to the communications group, wherein the bufferstatus report indicates the amount of the to-be-transmitted data waitingto be transmitted in the logical channel group between the terminaldevice and another terminal device; and send the transmissioninformation about to the base station.
 17. The communication deviceaccording to claim 16, wherein when the execution instruction isexecuted the device is enabled to receive from the base station,resource information about a resource allocated by the base station forthe communications group, the resource information including theidentification information of the communications group; and transmitcommunication data in the communications group by using the resource.18. The communication device according to claim 16, wherein theidentification information of the communications group is a groupidentifier for proximity service (ProSe).
 19. The communication deviceaccording to claim 16, wherein at least one of the buffer status reportincludes a buffer size, and the identification information of thecommunications group includes an index number of the communicationsgroup.
 20. The communication device according to claim 16, whereinsending of the transmission information about the amount of theto-be-transmitted data to the base station comprises: sending one MACcontrol element to the base station, the MAC control element includingthe transmission information of the communications group that hascommunication data to be sent.